Question

A large pot of water is heating up on a stove at a constant rate. After three minutes of heating it had a temperature of 100 ℉. After nine minutes of heating the temperature was at 148 ℉. Let T be the temperature and n be the number of minutes. Write a linear equation for T in terms of n.

Answer 1

T= 8n+76

Explanation:

First you need to find the average rate of change:

( 3, 100)

(9,148)

Subtract:

148-100= 48

9-3= 6

Then divide them:

48/6=8

This is your slope, now we must find our y- intercept by using the formula

y= mx+b:

y=mx+b

Plug in what you know:

y= 8x+b

To find your y-intercept use one of the 2 points above, either (3,100) or (9,148)

Plug in your x's and y's into your almost complete equation:

100= 8(3)+b

Then solve to get b:

You should get b=76

Hope this helps

Answer 2

Given function:

y=9.5x+62.1

We have to find the number of minutes x, when y=138.1°F

Put value of y in function.

138.1=9.5x+62.1

Subtract 62.1 from both sides.

76=9.5x

Divide both sides by 9.5.

8=x

or

x=8 minutes

Answer: After 8 minutes the temperature of water will be 138.1°

Explanation: